Sitting inside a car in just mildly hot weather can be dangerous, and potentially fatal. Here’s why.
In warmer weather, your car basically acts like a greenhouse. But the reason it gets so hot is not as simple as you might think. While sunlight hitting the car warms it up, it’s the infrared waves produced inside that are the real problem.
See, your car’s glass actually blocks longer wavelengths of light, like infrared, from entering. These are the wavelengths that radiate heat. But while they can’t get in, they also can’t get out.
As sunlight hits your car, the surfaces such as your steering wheel and dashboard try to re-radiate that incoming energy. They do so via infrared waves, so as The Weather Network notes, they “get rid of excess energy by radiating it as heat.”
The result is that the temperature inside your car can jump massively, even when the temperature outside is not that hot. Even if it’s just 21°C (70°F) outside, a car in sunlight can easily reach 50°C (122°F). You can suffer heat stroke if your body temperature reaches 40°C (104°F), or even less.
The Journal of Emergency Medical Services says that your car can jump a massive 11°C (20°F) if it’s left in the Sun for just 10 minutes. After 20 minutes, it can rise by 16°C (29°F). After an hour, most cars will reach a peak temperature of between 60-82°C (140-180°F). You will not survive long at these temperatures.
When the body is exposed to too much heat, hyperthermia begins. This is basically where our body is producing more heat than it can get rid of. Heart rate and breathing increase as your blood pressure drops. The latter can turn your skin pale or blue as your heart tries to circulate blood properly. Eventually, this can prove fatal as your organs fail.